The blue chips dip below 17,000 as Amazon, Visa disappoint. Requiem for an ace trader. Weakness at Wal-Mart. Tupperware aims to put a lid on its problems.

On a day when one of the most famous traders of the past 50 years passed away, investors briefly lost confidence in the market, sending the Dow Jones industrials into the red for the week and back under 17,000.

Economic news and earnings reports mostly have painted a sunny picture for the market in the past few sessions, but...